Industrial filtration

Various types of filter media and the materials oi which they are constructed are surveyed extensively by Purchas Industrial Filtration of Liquids, CRC Press, Cleveland, 1967, chap. 3), and characterizing measurements (e.g., pore size, permeabihty) are reviewed in detail by Rushton and Griffiths (in Orr, op. cit., chap. 3). Briefer summaries of classification of media and of practical criteria for the selec tion of a filter medium are presented by Shoemaker (op. cit., p. 26) and Purchas [Filtr Sep., 17, 253, 372 (1980)]. 

Industrial filtration systems may be of many types. The most common type is the baghouse shown in Fig. 29-3. The filter bags are fabricated from woven material, with the material and weave selected to fit the specific application. Cotton and synthetic fabrics are used for relatively low temperatures, and glass cloth fabrics can be used for elevated temperatures, up to 290 C. 

Conquest Equipment Corporation Industrial filtration products and services to clients in the wood, paper, plastics, metal, aerospace, and mining industries. http // vww.conauesteauipment.com... 

Matteson, M. S. and Orr, C. Filtration Principles and Practice, 2nd edn. (Marcel Dekker, New York, 1987). Purchas, D. B. Industrial Filtration of Liquids, 2nd edn. (Leonard Hill, London, 1971). 

CARMAN, P. C. Trans. Inst. Chem. Eng. 16 (1938) 168. Fundamental principles of industrial filtration. 

PURCHAS, D. B. Industrial Filtration of Liquids, 2nd edn. (Leonard Hill, London, 1971). 

Outstanding chemical resistance, serving industrial filtration High abrasion resistance for floor covering, upholstery, and hosiery Insensitive to water, giving dimensional stability and fabric dryness in contact with the skin... 

The study of problems concerning the flow of fluids through beds of granular material has many applications. It is indispensable to the theory of industrial filtration and water purification. The flow of ground water is controlled by soil structure and the most elementary phases of granular bed structure are fundamental to soil mechanics and soil physics. 

Continuous multicompartment drum filters, as illustrated in Fig. 14.9, are normally used on materials that are relatively concentrated and easy to filter. Rates of cake buildup are in the range of 0.05 in/min (0.0013 m/min) to 0.05 in/s (0.0013 m/s). Submergence normally runs from 25 to 75 percent (40 percent being quite common), with rotation speeds from 0.1 to 3 r/min. With these conditions, filtration times could range from 5 s to 7.5 min, the great majority of industrial filtration falling within these limits. 

The manufacturer of filter aids produces filter aid grades in a wide range of particle sizes to meet practically any industrial filtration requirement. The relative flow rates of these grades are determined by a standard filtration test and are shown in Fig. 4. Typical properties of some commercial filter aids are shown in Tables 1-3. Filter Cel, the finest grade, shown in Fig. 4, giving the highest clarity and lowest flow rate, is a natural diatomite, which has been selectively quarried, dried, milled, and air-classified. To make coarser, faster flow rate filter aids, Filter-Cel is calcined and air-classified. These straight... 

Diatomaceous earth filter aids are widely used in industrial filtration operations, and have evolved as an integral part in many other processes. Besides turbidities naturally occurring as a result of processing, diatomaceous earth filter aids are used to remove... 

According to the Industrial Filtration Corporation the rotary filter is indicated when the slurry will permit a cake K in. or more in thickness to build in 2 to 3 minutes when poured into a Buchner filter under 25 in. of suction. 

Purchas, D.B. 1967. Industrial filtration of liquids. Cleveland, OH CRC Press. 

In industrial filtration a common filter medium is canvas cloth, either duck or twill weave. Many different weights and patterns of weave are available for different services. Corrosive liquids require the use of other filter media, such as woolen cloth, metal cloth of monel or stainless steel, glass cloth, or paper. Synthetic fabrics like nylon, polypropylene, and various polyesters are also highly resistant chemically. 

For many industrial filtrations, the filter is supplied by a centrifugal pump or blower at practically constant pressure, so Pj - P3 is a constant, and Eq. 12.32 may be rearranged and integrated to... 

For a few industrial filtrations, the filter is upplied by a positive-displacement pump, which is practically a constant-flow-rate device. Such a pump feeds the filter at a pressure which is steadily increasing during the filtration. Equation 12.32 shows that for constant k and negligible a the pressure increases linearly with time, because the cake thickness increases linearly with time, ... 

It has been observed experimentally, and explained theoretically (Serrano, 1981), that the filtration behavior of a not very concentrated suspension, such as wine (particle content less than 1%), obeys different physical laws according to the type of porous material used to remove the solids. A mathematical model expresses the variations in volume filtered over time, at constant pressure, for each of these laws. The behavior of a given product in industrial filtration may be predicted on the basis of laboratory tests, by applying the corresponding equation. 

The Vmax value is used, together with the fouling index (Section 11.8.3), to predict the behavior of an industrial filtration process. 

It is thus possible to optimize an industrial filtration process in the laboratory and compare the... 

If the filter s surface area is known, the straight line giving the volume filtered during a normal industrial filtration cycle may be plotted on logarithmic paper from two or three experimental... 

Table 11.8 shows an example of industrial filtration, assessing the quality of clarification and, consequently, making it possible to select the filter sheets best adapted to this process. The results show that it is indispensable to use sufficiently fine filters to achieve perfect clarification just before bottling. The resulting loss of polysaccharides, a negative effect of filtration on quality, is negligible. 

A prefilter is normally used to protect the membranes and avoid excessively rapid fouling. An industrial filtration system includes a prefilter unit and a final filfrafion unit , assembled in series on the same base. 

Polyesters, such as PET are now widely used in the manufacture of fibers for textiles and other applications. While PET has many desirable properties that make it suitable for manufacturing fibers, there is a continuing need for polyester fibers that have improved properties, or properties that are different from PET, thereby opening new uses for polyester fibers. For example, PEN has found applications in high performance sailcloth materials or in industrial filtration applications. Micro fibers can be obtained from fibers using a laser thinning method. ... 

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